Rapid prosthetic rehabilitation on dental implants

In practice, we increasingly encounter the issue of rapid prosthetic rehabilitation on dental implants. Patients increasingly wish to receive a suitable replacement immediately, or at least soon after implant placement, which prompted us to write a few words about this topic.

The idea of implanting replacements for tooth roots or teeth is very old and dates back long before the beginning of our era. The first evidence of immediate implantation of foreign material into the jawbone after teeth had been knocked out is known from the period of the Maya Indians. After battle, they inserted pieces of seashell into fresh wounds at the sites of lost incisors. Examination of skeletal remains showed that these pieces had successfully and completely fused with the jawbone (osseointegration).
According to the time interval after tooth extraction, we generally distinguish two methods of placing dental implants into the jawbone:

Immediate implantation is suitable when the extracted or knocked-out tooth had not shown severe signs of disease before the event, such as extensive inflammation of the bone around the root apex. The X-ray image shows no presence of periapical granulomas. The clinical situation is clean, with no signs of purulent inflammation, swelling or fistulation (presence of a fistula or tract). Teeth that can be replaced immediately with an implant may have only one root: incisors, canines and premolars, because the anatomy of the root must at least approximately correspond to the shape of the dental implant. The thickness of bone separating the bottom of the socket (the bony bed of the root) from important anatomical structures must be sufficient for primary retention of the implant (after screwing, the implant must be anchored relatively firmly in the bone). In the upper jaw, the thickness of the bone is limited by the floor of the nasal cavity or the floor of the paranasal sinuses. In the lower jaw, the nerve that supplies all lower-jaw teeth as well as the lip and skin of the chin (mandibular nerve) lies in the way. The bone in which the tooth root was located must remain relatively undamaged after extraction or trauma so that, after insertion, the implant is surrounded by an adequate thickness of bone. Most often, the shape of the socket does not completely correspond to the shape of the dental implant. If the discrepancy between the size of the socket and the thickness of the implant is greater than two millimeters, artificial bone granules must be added into the gap between the bone and the implant. When the conditions are not suitable for immediate implantation, delayed implant placement is used at least two months after tooth extraction.

Immediate implantation naturally has its advantages. After extraction, the bone at the affected site usually undergoes considerable remodeling. The bony ridge becomes smaller (thinner and shorter), followed by remodeling of the soft tissue (gingiva). The result is an aesthetically unsatisfactory prosthetic replacement. Preservation of the original height of the bony ridge is of essential importance for preserving the interdental papillae (parts of the gingiva that fill the empty triangular spaces between dental crowns). By placing the implant immediately, remodeling of the bone and gingiva can largely be avoided. This method of implantation shortens the time to definitive prosthetic rehabilitation. In addition, the patient undergoes surgical treatment only once (implant placement and extraction at the same time).

According to the time interval before dental implants are loaded with prosthetic restorations, we distinguish two methods:

The classic method of implant placement follows the principle that, during the period of osseointegration (fusion with bone), the implant must not be loaded and therefore must not support a prosthetic restoration (crown, bridge, denture). Minimal movement of the implant caused by biting forces prevents successful fusion with the bone. In such a case, connective tissue forms around the implant and prevents direct contact with bone: this is referred to as fibrous integration and can be regarded as treatment failure. The periods implants need for osseointegration vary. In general, however, the intervals before loading can be divided into two groups:

The differences are determined by the different bone density in the upper and lower jaws, as well as in the incisor and molar regions. Throughout this period, patients are provided with temporary prosthetic restorations (removable or fixed) that do not load the implant. Temporary rehabilitation is usually aesthetically satisfactory, but functionally poor and insufficient. During this time, patients may therefore experience problems with effective chewing.

Time pressure and increasing emphasis on aesthetically refined solutions have led to treatment methods (immediate implant loading) that can provide immediate aesthetic and relatively good functional rehabilitation after surgery. In this case, minimal movements during the period in which the implant integrates with the bone are avoided by obtaining high primary retention of the inserted implant. This means that the implant thread itself and the force used to screw it into the bone prevent the implant from moving within the bony bed despite loading from chewing forces. Minimal movement is detrimental to successful osseointegration and therefore to treatment success. Of essential importance for good initial fixation of the implant is the insertion torque used when screwing self-tapping implants into bone, which should be approximately 40 N/cm. This force is determined by bone density, bone thickness, and the shape and length of the dental implants. The stated retention can be achieved in implants inserted immediately after tooth extraction or later, at least two months after extraction or traumatic loss of the tooth.

The prosthetic restoration used to load a dental implant immediately after placement must not be the same as the one the patient will receive only several months after surgery. The restoration must not be in full function, meaning that it does not contact the antagonists (teeth in the opposite jaw). These restorations are also most often made from softer materials than definitive ones. Because a temporary restoration is fabricated directly on the dental implant, this method of temporary rehabilitation is therefore somewhat more expensive than conventional temporary removable rehabilitation with delayed loading of implants. 

Leave the decision regarding the method of treatment with dental implants to the clinicians. We hope that the information provided will make it easier for you to decide on this type of treatment.